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Scientists Freeze Pulse Of Light
Smitty825 writes "After slowing down light to slow speeds, scientists at Harvard University have been able to stop light for a very brief period of time without destroying its energy. The article explains how it is different from this previous light-stopping science story - this will hopefully help the development of quantum computers and ways to communicate over long distances without being eavesdropped on."
Now if they could only figure out how to stop SPAM
Imagine going out to a club and getting a frozen "light cube" in your drink which releases a stream of photons as it melts.
Could bring a whole new dimesnion to the humble Tequila Sunrise huh?
A little planning goes a long way...
Oh...wait. Voids allow light to travel faster. shame on me. What color is stopped light if it retains its energy?
~mingust
Makes me think of a physics joke.
Q: What is the difference between stopped light and darkness?
A: You know where darkness is.
I thought that light is a visual thing. How does one "eavesdrop" on light?
From excellent karma to terible karma with a single +5 funny post...
The article mentions clearly:
"We have succeeded in holding a light pulse still without taking all the energy away from it," said Mikhail D. Lukin, a Harvard physicist.
This is somehow different from "...without destroying its energy." like it is stated in the posting. Maybe a subtle detail, but not quite the same.
However, a briliant achievement. Kuddos.
If the NSA supposedly managed to tap into fiber (light) what makes this guy so sure his studies would minimize/cut/halt the risk of eavesdropping? "Splice the line, and you cut off the light, at least momentarily," says Wayne Siddall, an optical engineer at Corning Fiber in Corning, N.Y. Even a second's interruption could be noticed by a cable's operator. Cable companies typically build systems with duplicate lines that take diverging routes, in case one of them is damaged or severed. One retired NSA optical specialist insists that the NSA devised a way to splice a fiber without being detected. "Getting into fiber is delicate work, but by no means impossible," the former specialist says. Neither he nor the NSA will discuss the matter further.
Spy agency taps into undersea cable
NSA Tapping Underwater Fiber Optics
And the list goes on and on. Bear in mind the NSA's date of achieving this, in comparison to the tech growth scale, I'd be willing to say that whatever Harvard is doing in being closely watched, if not already known.
MoFscker
Sounds like you could use it similar to the initial version of electronic memory (sort of a digital delay line), if it could be harnessed.
:-)
A few hundred-thousandths of a second is an eternity(*) for a photon. That's actually pretty impressive
Simon.
(*) Yes, for the pedants amongst us, I realise it's not actually an eternity. It's a figure of speech, for chrissake!
Physicists get Hadrons!
BBC News has an article which speaks a bit more to Quantum crytography.
"Quantum cryptography might provide very secure forms of electronic encryption, because the process of eavesdropping on an electronic message would introduce errors in the message, garbling it."
"This would allow you to exchange a key on a public channel, but whereas any classical system can be broken by an eavesdropper, in quantum cryptography you would always find out if someone was looking at your message," Professor Zubairy told BBC News Online."
"Academicians are more likely to share each other's toothbrush than each other's nomenclature."
Cohen
Could "Slow Glass" be coming? Bob Shaw wrote about glass that could slow down light so that it took years to pass through and the effects it had on society in his 1972 book Other Days, Other Eyes. Anyone interested in this stuff should hunt down a copy.
Like I did here.
More detailed articles about the research can be found here or here.
Larkin's article itself is here.
Any physics nerds want to explain it to us?
Here's a quote from Terry Pratchett you might like:
"Light thinks it travels faster than anything but it is wrong. No matter how fast light travels it finds the darkness has always got there first, and is waiting for it."
Why were there no pictures of this stopped light? .. oh wait
Officer: "Do you know how fast you were going?"
Heisenberg: "No, but I know exactly where I am!"
paintball
I once read an SF short story that featured windowpanes which light took decades to pass through - thereby letting you look at the past.
The story included the poignant scene of the protagonist looking out at his wife and child playing in the garden - but they had died 15 years earlier. The character used to hang around near the windows, hoping for glimpses of his dead wife, because he, of course, had no control over when he saw her; the windows would "replay the past" in strict linear sequence.
Does anyone know the name & author of the story?
In the story, the windowpanes were made of optical fibre nanotubes that were so tightly coiled up in the windows that the windows could accomodate tubes a few light-years long.
This research suggests more feasibly ways of doing this, though.
Light doesn't actually have "color". Color is our perception of the wavelength of the light. There's another article on BBC that explains the experiment in greater detail. Essentially, they didn't actually freeze the photons, ie. made them stop moving, but used a different method to make the photons bounce back and forth in place. So the "color" should have remained the same.
I am just building my reasoning backwards. To understand what happens to the Photon when it stops, let's first see what happens to the photon when it moves at - well - the speed of light.
From the quickest reference I could dig thru http://www.wired.com/wired/archive/6.07/es_warp.ht ml?pg=3&topic=
So, the faster the photon moves the slower the clocks would appear to move. Then, I guess, the slower the Photon moves the faster the clock would appear to move. And when the photon STOPS, the clock must be moving INSANELY FAST. So how could it be a very brief period of time ? .. I think it is a very very very long period of time.
Guess, it all depends on which perspective you are looking at, and how you are measuring time ...
To see a world in a grain of sand, and then to step back and see the beach where the sand lies
We have the technology to create a lightsaber. I know what I'm asking Santa for Christmas now.
It was just slashdotted, and completely unable to move under the load.
I think you're missing the point.
These experiments are all a stepping stone towards genuine quantum communication. Previous experiment such as those in Paris (by firing rhubidium through a photon of light)showed that scientists can no measure certain properties of light without destroying the photon, and then re-measure it. The problem was that for quantum communication, you need to disentangle 2 separate photons from an entangled state so that any change you make to one makes ann instantaneous change to the other, it's twin if you like and that can be done it seems. But, keeping the light fixed in a certain place is one of the tricky parts. If they ever succeed at refing these crystals to the extent that a photon can be kept in a deterministic state, then all you need is 2 of these crystals - you can imagine them being placed at opposite ends of our solar system, each crystal containing your premade entangled photon bouncing back and forth, with the crystal itself locked in some kind of black box (cavity).
Presumablt the crystals would have small atomic/sub/atomic sized pin holes to fire the rhubidium or other material through one of the crystals. The the phase shif of the rhubidium caused by this firing also occurs at the other photon (because they are entangled). Then when you measure the phase shift of the second crystal, the difference is twice as great (i.e. the first phase shift plus the second phase shift0 - hence you know at the other end of the solar system, that it was fired. Now all you need is a model, to measure
according to time, t. For example, one crystal could measure every odd microsecond, the other at every even microsecond.
Now you have a unary turing machine, communicating between the stars!!!.
What's wrong with 'Does this smell like chloroform to you?'
As for the frozen light, I'm thinking this will herald a new line in novelty items of the type sold at Spencer Gifts, only to be shoved in a cupboard two days later and never seen again.
Could this lead to harvisting light? As in, freeze large areas (100-1000m3) of light and then using the light to produce energy?
Im not pretending to know what im talking about but it sounds as if one day we'll be able to cut light right out of the sky for where we dont need light, like on the moon or other planets. I was going to say antartica or the ocean but then i thought we'd prolly all die in huge freek weather storms or feeze to death.
But being able to harvest light could be a pretty cool advancement for our growing energy needs. Maybe would could harvest it with huge satelites orbiting the sun and have the light transported back as high energy lazers?
Giving IE users a taste of their own medicine since 2005 - http://pods.-is-a-geek.net/
And if we can hook him up to a dynamo and a generator, we've got free energy sorted. Truly, this is an age of wonders.
They've got it all backwards. They're supposed to be working on a way to increase the speed of light. How else are we going to accomplish a practical form of interstellar travel?
Hee-hee. Dying tickles!
no, that's false. the universal speed limitation is the speed of light in a vacuum. Because light passing through matter moves slower than it does through a vacuum, it's perfectly possible to move faster than the "local" speed of light. Physicists have studied this by firing high-speed particles into crystals. Basically the particle creates a shockwave, a sort of optical equivalent of a sonic boom. It's called Cherenkov radiation if you want to look it up.
The author of this post asserts his moral rights.
Sorry friend, but he is correct and you are wrong.
He stated the 'color' of our photo receptors. Although our photo receptors pick up C, Y, and M -- it is because their colors (as he said) are R, G, and B.
ie: the Red Photoreceptor reflects RED, that is why it is a red colored photoreceptor. Since it reflects RED, it picks up BLUE and GREEN, which make one of the (secondary) colors you mentioned.
You are also wrong saying that RGB is used for pigment. Pigment gets its color by absorbing color, and you see what is reflected. RGB is used for TVs and Monitors where there is a direct source of light.
Cheers!